A std::pair is an ordered, heterogeneous sequence of exactly two objects (it is a special case of std::tuple).
std::pair is a part of the C++ Standard Library, defined in the header <utility>.
Questions tagged [std-pair]
776 questions
-2
votes
3 answers
Which method is to access Pairs?
just to clear this doubt of fine i just want to ask that which method is faster or more efficient to access pairs while iterating over a contiguous block of pairs.
I used two method to iterate over a block.
1st
pair arr[3] = {{1, 'a'},…
Vasu saini
- 21
- 6
-2
votes
2 answers
Why do return boolean value in this line std::unordered_map<>.insert().second in C++
std::unordered_map url;
url.insert(std::pair("google","www.google.co.kr"));
bool ok = url.insert(std::pair("google","www.google.com")).second;
std::cout << (ok ?…
Kwon34
- 11
-2
votes
1 answer
Is there a size() member function for std::pair?
I was following a hash table implementation tutorial and came across this:
class HashTable {
private:
static const int hashGroups = 10;
std::list> table[hashGroups];
bool HashTable::isEmpty() const {
int…
Yamato Eguchi
- 13
- 4
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votes
1 answer
In c++ code, set.erase(it) is halting execution, where it=set.begin() for a set of pairs, why is this happening?
Sorry for any inconvenience I am a beginner at C++ and was stuck with an empty set... Thank you for the helpful comments that helped me figure out what the problem was
I wrote a C++ code for a question in which I need to use Dijkstra's shortest path…
costheta_z
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-2
votes
3 answers
warning: character constant too long for its type car.second = 'Sarim';
I want to make a pair of int and string.
As:
pair car ;
car.first = 10;
car.second = 'Sarim';
cout<
SARIM
- 992
- 3
- 14
- 22
-2
votes
2 answers
How to push a value inside a vector which in a c++ pair?
I have come across a scenario where I am not able to find a way to push a value in the vector which is in the pair. I have made a priority_queue of pair> and I want to push values in the vector, for…
hitesh kumar
- 3
- 3
-2
votes
2 answers
Why std::pair doesn't compare with std::string?
Why I can't compile the code bellow?
string m = "MEOW";
pair p = { "M", 0 };
if (m[0] == p.first)
p.second += 10;
I get the error:
main.cpp:18:14: error: invalid operands to binary expression ('int' and…
Jeffy
- 71
- 1
- 5
-2
votes
2 answers
Accessing values of a map that containing a vector pair
I declared a map that contains a vector pair like
typedef vector> vectorPair;
map mapName;
I've been trying to iterate through the map with an iterator and I'm confused as to how I access the vector pair from…
user10416464
-2
votes
2 answers
How to insert an element in a vector of pair of set? vector>>
vector>>m1;
I am trying to insert an element where each int will hold several strings using set. How to insert an element in this?
I tried like this.
vector>>m1;
int p,n,i;
cin>>p>>n;
…
Joy Sinha
- 11
- 2
-2
votes
2 answers
Return only the first element of an std::pair when calling a function that returns std::pair
I'm using a function that returns an std::pair:
std::pair myFunction() {
//Do something...
if (success) {
return {true, someValue};
}
else {
return {false, someOtherValue};
}
}
On success, the pair's…
Julini
- 45
- 1
- 7
-2
votes
1 answer
Find unique quadruplets in C++
So, I need to find unique quadruples in C++. Any idea would help
Input 1 : [1, 0, 2, 3], [2, 0, 1, 3], [4, 5, 6, 7], [8, 9, 10, 11]
Output 1 : [2, 0, 1, 3], [4, 5, 6, ,7], [8, 9, 10, 11]
As [1,0,2,3] and [2,0,1,3] both contain same elements so…
pranavhd
- 25
- 7
-2
votes
2 answers
Pair cpp or use a map to fill and print
I dont know how to include a map or a pair in this code below to print ou a list in format A:1 B:2 C:3
#include
using namespace std;
#include
Tahtoh
- 75
- 1
- 10
-2
votes
2 answers
Printing the elements of vector
In the following code, I have a 2D vector,in each index of vector each pair contains int and string. I am trying to access the each element after taking the values in the vector. Suggestions will be very much appreciated.
#include
…
Shovo
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- 9
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votes
1 answer
Using a pair as a parameter from another function
I asked this question before but the suggestions don't work so I have tried to make my question more clear.
I have a function that returns a std::pair but the parameters for the function as follow function(int g, double a);. This…
May
- 15
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- 3
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votes
1 answer
How to get a C++ pair to compile
I am trying to compile a very complicated code and I get the error
g++ -o MCBody MCBody.cpp
MCBody.cpp:36:34: error: expected initializer before ‘<’ token
double numericalIntegration::pair integrate(double (*pFun)(const double &…
ianacp
- 9
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